User-assembled free weights

ABSTRACT

A user-assembled free weight includes a container made of a contiguous material and having at least one cavity. A heavy curable fill material is placed inside the at least one cavity. Together the heavy curable fill material and the container produce at least a target weight and the heavy curable fill material is non-removable from the container.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation-in-part of and claims priority of U.S. patent application Ser. No. 17/496,176, filed Oct. 7, 2021, which is based on and claims the benefit of U.S. provisional patent application Ser. No. 63/089,129, filed Oct. 8, 2020, the content of which is hereby incorporated by reference in its entirety.

BACKGROUND

Dumbbells, kettlebells and weight plates are free weights used in weight training that do not constrain a user to specific, fixed movements. A dumbbell includes the familiar structure of a handle with a weight or weights and may be used individually or in pairs. Commercially available dumbbells are manufactured to be of metal, such as cast iron or steel, sometimes coated with rubber or neoprene for comfort. A kettlebell is a cast iron or cast steel ball with a handle attached to the top and may be used to perform many types of load bearing exercises, such as ballistic exercises that require cardiovascular, strength and flexibility training. Unlike a dumbbell, a kettlebell's center of mass is extended beyond the hand, this allows for swinging movements. A weight plate may come in all shapes or sizes, are manufactured to be of metal, such as cast iron or steel, and sometimes coated with rubber or urethane. Weight plates may be used with regular or standard weight lifting bars and provide for flexibility in changing the amount of weight being lifted by changing the number and size of plates.

The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter.

SUMMARY

A user-assembled free weight includes a hollow container made of a contiguous material and having a length, a width and a height, the hollow container comprises a first end wall that includes an opening for access into an interior of the container; a second opposing closed end wall; a first side wall that extends from the first end wall to the second end wall and defines the length of the container and an opposing second side wall spaced apart from the first side wall, extends from the first end wall to the second end wall and defines the length of the container. A first widthwise wall is spaced apart from the first end wall to define the interior of the container. A second widthwise wall is spaced apart from the second end wall to define the interior of the container. A first lengthwise wall is spaced apart from the first side wall to define the interior of the container and connect the first widthwise wall to the second widthwise wall. A second lengthwise wall is spaced apart from the second side wall to define the interior of the container and connect the first widthwise wall to the second widthwise wall. A hollow handle extends from the first widthwise wall to the second widthwise wall and is spaced apart from the first lengthwise wall and from the second lengthwise wall. A heavy curable material is placed inside the container through the opening in the first end wall. The heavy curable fill material is located inside the container and the handle and being non-removable. The opening in the first end wall has a width that is less than a width of the first end wall and at least as great as a distance between the first lengthwise wall and the second lengthwise wall.

A user-assembled free weight has a hollow container made of a contiguous material and includes a first end cavity defined between a first end wall having an opening for access into an interior of the container and a first widthwise wall and between a first side wall and a second side wall. A second closed end cavity is defined between a second closed end wall and a second widthwise wall and between the first side wall and the second side wall. A first connecting cavity connects the first end cavity to the second end cavity and is defined between the first side wall and a first lengthwise wall. A second connecting cavity is spaced apart from the first connecting cavity that connects the first end cavity to the second end cavity and is defined between the second side wall and a second lengthwise wall. A hollow handle extends from the first widthwise wall to the second widthwise wall and is spaced apart and located between the first lengthwise wall and the second lengthwise wall. A heavy curable material is placed inside the container through the opening in the first end wall. The heavy curable fill material is located inside the container and the handle and is non-removable. A height of the first connecting cavity and the second connecting cavity are less than a height of the first end cavity and the second end cavity.

A user-assembled free weight has a hollow container made of a contiguous material and includes a first end cavity defined between a first end wall having an opening for access into an interior of the contain and a first widthwise wall and between a first side wall and a second side wall. A second closed end cavity is defined between a second closed end wall and a second widthwise wall and between the first side wall and the second side wall. A first connecting cavity connects the first end cavity to the second end cavity and is defined between the first side wall and a first lengthwise wall. A second connecting cavity is spaced apart from the first connecting cavity that connects the first end cavity to the second end cavity and is defined between the second side wall and a second lengthwise wall. A hollow handle extends from the first widthwise wall to the second widthwise wall and is spaced apart and located between the first lengthwise wall and the second lengthwise wall. A heavy curable material is placed inside the container through the opening in the first end wall. The heavy curable fill material is located inside the container and the handle and is non-removable. At least one of the first lengthwise wall and the second lengthwise wall has an outer facing surface that faces the hollow handle and includes a recess having an arcuate surface.

This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the background.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating a user-assembled free weight or dumbbell that includes a container and a fill according to an embodiment.

FIG. 2 is a perspective view illustrating the container of FIG. 1 without fill according to an embodiment.

FIG. 3 is a first side view of FIG. 1 .

FIG. 4 is a second side view of FIG. 1 .

FIG. 5 is a first end view of FIG. 1 .

FIG. 6 is a second opposing end view of FIG. 1 .

FIG. 7 is a section view of FIG. 1 taken through the section line indicated in FIG. 3 .

FIG. 8 is a section view of FIG. 1 taken through the section line indicated in FIG. 3 but according to another embodiment.

FIG. 9 is a perspective view illustrating a user-assembled free weight or kettlebell that includes a container and a fill according to an embodiment.

FIG. 10 is a perspective view illustrating the container of FIG. 9 without fill according to an embodiment.

FIG. 11 is a front view of FIG. 9 .

FIG. 12 is a left side view of FIG. 9 .

FIG. 13 is a first end view of FIG. 9 .

FIG. 14 is a second opposing end view of FIG. 9 .

FIG. 15 is a section view of FIG. 9 taken through the section line indicated in FIG. 12 .

FIG. 16 is a perspective view illustrating a user-assembled free weight or dumbbell that includes a container and a fill according to an embodiment.

FIG. 17 is a perspective view illustrating the container of FIG. 16 without fill according to an embodiment.

FIG. 18 is a first side view of FIG. 16 .

FIG. 19 is a second side view of FIG. 16 .

FIG. 20 is a first end view of FIG. 16 .

FIG. 21 is a second opposing end view of FIG. 16 .

FIG. 22 is a section view of FIG. 16 taken through the section line indicated in FIG. 18 .

FIG. 23 is a perspective view illustrating a user-assembled free weight or weight plate that includes a container and a fill according to an embodiment.

FIG. 24 is a perspective view illustrating the container of FIG. 23 without fill according to an embodiment.

FIG. 25 is a section view of FIG. 24 .

FIG. 26 is an exploded perspective view of the empty container of FIG. 24 and a fitting according to an embodiment.

FIG. 27 illustrates an assembled perspective view of FIG. 26 .

FIG. 28 is a first end perspective view illustrating a user-assembled free weight or dumbbell that includes a container according to an embodiment.

FIG. 29 is an opposing second end perspective view of FIG. 28 .

FIG. 30 is a side view of FIG. 28 .

FIG. 31 is a bottom view of FIG. 28 .

FIG. 32 is a section view of the user-assembled free weight of FIG. 28 taken through the section line illustrated in FIG. 29 .

FIG. 33 is a section view of the user-assembled free weight of FIG. 28 taken through the section line illustrated in FIG. 31 .

FIG. 34 is a first end perspective view illustrating a user-assembled free weight or dumbbell that includes a container and fill according to an embodiment.

FIG. 35 is an opposing second end perspective view of FIG. 34 .

FIG. 36 is a side view of FIG. 34 .

FIG. 37 is a bottom view of FIG. 34 .

FIG. 38 is a section view of the user-assembled free weight of FIG. 34 taken through the section line illustrated in FIG. 35 .

FIG. 39 is a section view of the user-assembled free weight of FIG. 34 taken through the section line illustrated in FIG. 37 .

FIG. 40 illustrates a user holding a handle of a the user-assembled free weight of FIG. 34 under an embodiment.

FIG. 41 is a front perspective view of two of the user-assembled free weights of FIG. 34 in a configuration where they are engaged with barbell according to an embodiment.

FIG. 42 is a side perspective of FIG. 41 .

DETAILED DESCRIPTION

When purchasing free weights online, product and shipping costs are high due to the materials of the product and the weight of the product causing oversize charges. Described below are user-assembled free weights that include empty containers shaped as dumbbells, kettlebells or weight plates or the like and are fillable, by the user at home, with a heavy fill or heavy curing materials, such as concrete, to function as dumbbells, kettlebells or weight plates. These user-assembled frees weight can be used in the comfort of the user's own home and at a fraction of the cost of free weights on the market.

FIG. 1 is a perspective view illustrating a user-assembled free weight or dumbbell 100 according to one embodiment. Free weight or dumbbell 100 includes a container 102 in the shape of a dumbbell and a heavy fill material 104 located inside container 102. FIG. 2 is a perspective view illustrating container 102 of free weight 100 without fill material 104. Under one embodiment, heavy fill material 104 is a curing material, such as concrete, that after being poured into container 102 cures inside container 102 and is non-removable from container 102. In other embodiments, heavy fill material 104 may be removable from container 102 and include a granulated material, such as sand, or a liquid material, such as water. Container 102 is designed to fit a precise amount of fill 104 leading to or producing at least a target weight. For example, FIG. 2 illustrates container 102 that will ultimately have a target weight of 40 pounds when filled with the heavy curing material concrete. Correct capacity is determined using the industry standard of 0.087 pounds per cubic inch of cured concrete. It should be understood that while empty container 102 is the product shipped to the user, the assembled, completed product 100 includes plastic container 102 permanently wrapped around fill 104. In addition, it should be realized that the dimensions of container 102 may change to form dumbbell 100 of any target weight is also possible.

In one embodiment, container 102 may be made of an opaque material, transparent material or have some degree of transparency. Material made of a transparent or some degree of transparency allows the user to visually see fill 104 moving down container or mold 102 during the fill or pour to ensure there are no air pockets. The user can either shake the container while it is filling to ensure no air spaces or use a tool, such as an elongated stick. For example, container 102 may be made of a plastic including a thermoplastic such as high-density polyethylene (HDPE), acrylonitrile butadiene styrene (ABS), polycarbonate (PC) or low-density polyethylene (LDPE). Not only are these exemplary materials crack and scratch resistant, these exemplary materials will protect fill 104 as well as the floor in the event a dumbbell is dropped. Regardless, the material of container 102 is thick enough to provide extra support for all corners of the container or mold when filled with fill 104.

FIG. 3 illustrates a first side view, FIG. 4 illustrates a second side view, FIG. 5 illustrates a first end view and FIG. 6 illustrates a second opposing end view of user-assembled free weight 100. FIG. 7 is a section view of user-assembled free weight 100 taken through the section line indicated in FIG. 3 . Hollow container or mold 102 may be manufactured by blow molding and includes a single, contiguous material that has a first cavity 106, an opposing second cavity 108 and a hollow handle 110 coupling first cavity 106 to second cavity 108 or interposed between first cavity 106 and second cavity 108. Hollow handle 110 is defined by a diameter 122 and includes an outer surface 116. Outer surface 116 includes a contiguous texture intended to improve grip for users. Under one embodiment, diameter 122 may be 1.41 inches.

Each cavity 106 and 108 includes a length 112, a width 114 and a height 115. Width 114 is greater than height 115 and width 114 and height 115 are greater than length 112. Under one embodiment, length 112 may be approximately 5.32 inches, width 114 may be approximately 8.13 inches and height 115 may be approximately 7.20 inches. An end 107 of first cavity 106 includes an opening 132. Opening 132 in FIGS. 1-2 and 5 is illustrated as being round. However, other shapes are possible including rectilinear, non-rectilinear and oval shapes as long as opening 132 is wide enough to fit most curing material tools, such as a concrete trowel, and to allow for easy transfer of fill 104 into the inside of container or mold 102 through opening 132 including inside cavities 106 and 108 and hollow handle 110. With opening 132 extending through end 107 of first cavity 106 of container 102, an opposing end 109 of second cavity 108 can provide a level side that is supported by the floor or ground to allow container 102 to stand vertically while pouring fill and letting fill dry or cure.

Opening 132 should not be wider than width 114 and height 115 of cavity 106 and may be configured to receive a cap or lid so that after fill 104 is cured or dried, the non-removable fill is hidden or protected from environmental exposure. In other embodiments, the cap or lid is configured to retain removable fill, such as granulated material or liquid material, inside container 104. Under one embodiment, opening 132 includes a diameter 134. Diameter 134 may be approximately 3.96 inches. Surrounding opening 132 is a lip 136 that protrudes from end 107 of cavity 106 by a length 137. The protrusion of lip 136 may be curved or straight, but should include an angle so that if fill 104 does crack, cracked pieces do not come out of opening 132. As illustrated in FIG. 7 , fill 104 is located from end 109 of second cavity 108 to end 107 of first cavity 106. Fill 104 should not be filled inside lip 136.

Between hollow handle 110 and first cavity 106 is a first hollow flared portion 118. In one embodiment, first hollow flared portion 118 is a circular flare that couples a first end 111 of hollow handle 110 having diameter 122 to first cavity 106. First hollow flared portion 118 includes a first open area located at an intersection 119 between first cavity 106 and first hollow flared portion 118 and a second open area located at first end 111 of hollow handle 110. The first open area is calculated by finding the product of πr² where r is the radius of the circular opening of first hollow flared portion 118 at first cavity 106 and second open area is calculated by finding the product of πr² where r is the internal radius of hollow handle 110. As illustrated, first open area is greater than second open area. Sides of first hollow flared portion 118 include a straight taper or straight flare. It should be realized that curved flares are also possible. Sides of first hollow flared portion 118 are defined by an angle 130 measured with respect to end 107 of first cavity 106. Generally, angle 130 can range from 20 to 60 degrees including 30 degrees (as illustrated). However other angles are possible as long as there is a transitional angle from hollow handle 110 to cavity 106 that is less than 90 degrees. As also illustrated, a wall 117 of cavity 106 that opposes end 107 and couples side walls of cavity 106 with first hollow flared portion 118 is angled by an angle 131 with respect to end 107 of first cavity 106. Generally, angle 131 can range from 0 to 60 degrees including 5 degrees (as illustrated). However other angles are possible as long as wall 117 provides a transitional angle from first hollow flared portion 118 into first cavity 106 that is less than 90 degrees.

Between hollow handle 110 and second cavity 108 is a second hollow flared portion 120. In one embodiment, second hollow flared portion 120 is a circular flare that couples a second end 113 of hollow handle 110 having diameter 122 to second cavity 106. Second hollow flared portion 120 includes a third open area located at an intersection 123 between second cavity 108 and second hollow flared portion 120 and a fourth open area located at second end 113 of hollow handle 110. The third open area is calculated by finding the product of πr² where r is the radius of the circular opening of second hollow flared portion 120 at second cavity 108 and fourth open area is calculated by finding the product of πr² where r is the internal radius of hollow handle 110. As illustrated, third open area is greater than fourth open area. Sides of second hollow flared portion 120 include a straight taper or straight flare. It should be realized that curved flares are also possible. Sides of first hollow flared portion 120 are defined by angle 130 measured with respect to end 109 of second cavity 108. Generally, angle 130 can range from 20 to 60 degrees including 30 degrees (as illustrated). However other angles are possible as long as there is a transitional angle from hollow handle 110 to cavity 108 that is less than 90 degrees. As also illustrated, a wall 121 of cavity 108 that opposes end 109 and couples side walls of cavity 108 with second hollow flared portion 120 is angled by angle 131 with respect to end 109 of second cavity 108. Generally, angle 131 can range from 0 to 60 degrees including 5 degrees (as illustrated). However other angles are possible as long as wall 121 provides a transitional angle from second hollow flared portion 120 into second cavity 108 that is less than 90 degrees.

First hollow flared portion 118 connects hollow handle 110 to first cavity 106 and second hollow flared portion 120 connects hollow handle 110 to second cavity 108. All flared portions 118 and 120 create a secure bond for fill 104 to run into and out of hollow handle 110, to reduce pressure on the middle of handle 110 caused by fill 104 in cavities 106 and 108 and to act like a funnel in guiding fill 104 throughout the hollow interior of container 102.

FIG. 8 is a section view of user-assembled free weight 100 taken through the section line indicated in FIG. 3 and according to another embodiment. While filling container 102 with fill 104, a rebar core 140 may be placed down through hollow handle 110 and extend through second cavity 108, handle 110 and first cavity 106. Rebar core 140 may be best placed after fill 104 has filled second cavity 108 and handle 110 and has begun to fill first cavity 104. Rebar core 140 may also be used to eliminate air pockets and make sure fill 104 fills the entirety of the volume of the interior of container 102. Rebar 140 is configured to take pressure off handle 110 and transfer pressure to rebar 140. Fill 104 is then less likely to crack when free weight 100 is dropped.

FIG. 9 is a perspective view illustrating a user-assembled free weight or kettlebell 200 according to another embodiment. Free weight or kettlebell 200 includes a container or mold 202 in the shape of a kettlebell and a heavy fill 204 (See FIGS. 14 and 15 located inside container 202. FIG. 10 is a perspective view illustrating container 202 without fill 204. Under one embodiment, heavy fill material 204 is a curing material, such as concrete, that after being poured into container 202 cures inside container 2202 and is non-removable from container 202. In other embodiments, heavy fill material 204 may be a granulated material, such as sand, or a liquid material, such as water. Container 202 is sized to fit a precise amount of fill 204 leading to or producing at least a target weight. For example, FIG. 10 illustrates container 202 that will ultimately have a target weight of 40 pounds when filled with concrete. Correct capacity is determined using the industry standard of 0.087 pounds per cubic inch of cured concrete. It should be understood that while empty container 202 is the product shipped to the user, the assembled, completed kettlebell 200 includes plastic container 202 permanently wrapped around fill 204. In addition, it should be realized that the dimensions of container 202 may change to form kettlebell 200 of any target weight is also possible.

In one embodiment, container 202 may be made of an opaque material, transparent material or have some degree of transparency. A transparent material will allow a user to visually see fill 204 in container or mold 202 during the fill or pour to ensure there are no air pockets. The user can either shake the container while it is filling to ensure no air spaces or use a tool, such as an elongated stick. For example, container 202 may be made of a transparent plastic including a thermoplastic such as high-density polyethylene (HDPE), acrylonitrile butadiene styrene (ABS), polycarbonate (PC) or low-density polyethylene (LDPE). Not only are these exemplary materials transparent and crack and scratch resistant, these exemplary materials will protect fill 204 as well as the floor in the event a kettlebell is dropped. Regardless, the material of container 202 is thick enough to provide extra support for all corners of the container or mold when filled with fill 204.

FIG. 11 illustrates a front view, the back view being identical, FIG. 12 illustrates a left side view, the opposing right side view begin identical, FIG. 13 illustrates a first end view and FIG. 14 illustrates a second end view. FIG. 15 is a section view of user-assembled free weight 200 taken through the section line indicated in FIG. 12 . Hollow container or mold 202 may be manufactured by blow molding and includes a single, contiguous material that has a main cavity 206 and a hollow handle 210 coupled to main cavity 206. Hollow handle 210 is defined by a diameter 222 and includes an outer surface 216. Under one embodiment, diameter 222 may be 1.75 inches.

An end 207 of main cavity 206, which is also a bottom end of kettlebell 200, includes an opening 232. Opening 232 in FIG. 14 is illustrated as being round. However, other shapes are possible including rectilinear, non-rectilinear and oval shapes as long as opening 232 is wide enough to fit most curing material tools, such as a concrete trowel, and to allow for easy transfer of fill into the inside of container or mold 202 through opening 232.

Opening 232 should not be wider than width 214 and height 215 of cavity 206 and may be configured to receive a cap or lid so that after fill 204 is cured or dried, the non-removable fill is hidden or protected from environmental exposure. In other embodiments, the cap or lid is configured to retain removable fill, such as granulated material or liquid material, inside container 204. Under one embodiment, opening 232 includes a diameter 234. Surrounding opening 232 is a lip 236 that protrudes from end 207 of cavity 206 by a length 237. The protrusion of lip 236 may be curved or straight, but should include an angle so that if fill 204 does crack, cracked pieces do not come out of opening 232. As illustrated in FIG. 15 , fill 204 is located from handle 210 to end 207 of main cavity 206. Fill 204 should not be filled inside lip 236.

Hollow handle 210 is coupled to main cavity 206 by first and second flared portions 218 and 220. In one embodiment, first and second flared portions 218 and 220 are elliptical lofted paths necking from main cavity 206 to circular hollow handle 210 as shown in detail in the phantom view of container 202 in FIG. 10 . Between a first end 211 of hollow handle 210 and main cavity 206 is a first hollow flared portion 218. First hollow flared portion 218 includes a first open area located at an intersection 219 between cavity 206 and first hollow flared portion 218 and a second open area located at first end 211 of hollow handle 210. As illustrated, the first open area of first hollow flared portion 218 is greater than the second open area of first hollow flared portion 218.

Between a second end 213 of hollow handle 210 and main cavity 206 is a second hollow flared portion 220. Second hollow flared portion 220 includes a third open area located at an intersection 223 between cavity 206 and second hollow flared portion 220 and a fourth open area located at second end 213 of hollow handle 210. As illustrated, the third open area of second hollow flared portion 220 is greater than the fourth open area of second hollow flared portion 220.

First and second flared portions 218 and 220 couple hollow handle 210 to main cavity 206 to create a more secure bond for fill 204 to run into hollow handle 210, to reduce pressure to allow fill 204 to flow from opening 232 through main cavity 206 to handle 210 easier and well as to create more strength for the corners once fill 204 has cured or dried.

FIG. 16 is a perspective view illustrating a user-assembled free weight or dumbbell 300 according to another embodiment. Free weight or dumbbell 300 includes a container or mold 302 and a heavy fill material 304 located inside container 302. FIG. 17 is a perspective view illustrating container 302 of free weight 300 without fill material 304. Under one embodiment, heavy fill material 304 is a curing material, such as concrete, that after being poured into container 302 cures inside container 302 and is non-removable from container 302. In other embodiments, heavy fill material 304 may be a granulated material, such as sand, or a liquid material, such as water. Container 302 is designed to fit a precise amount of fill 304 leading to or producing at least a target weight. For example, FIG. 17 illustrates container 302 that will ultimately weigh 80 pounds when filled with concrete. Correct capacity is determined using the industry standard of 0.087 pounds per cubic inch of cured concrete. It should be understood that while empty container 302 is the product shipped to the user, the assembled, completed product 300 includes plastic container 302 permanently wrapped around fill 304. In addition, it should be realized that the dimensions of container 302 may change to form dumbbell 300 of any target weight is also possible.

In one embodiment, container 302 may be made of an opaque material, transparent material or have some degree of transparency. Material made of a transparent or some degree of transparency allows the user to visually see fill 304 moving down container or mold 302 during the fill or pour to ensure there are no air pockets. The user can either shake the container while it is filling to ensure no air spaces or use a tool, such as an elongated stick. For example, container 302 may be made of a plastic including a thermoplastic such as high-density polyethylene (HDPE), acrylonitrile butadiene styrene (ABS), polycarbonate (PC) or low-density polyethylene (LDPE). Not only are these exemplary materials crack and scratch resistant, these exemplary materials will protect fill 304 as well as the floor in the event a dumbbell is dropped. Regardless, the material of container 302 is thick enough to provide extra support for all corners of the container or mold when filled with fill 304.

FIG. 18 illustrates a first side view, FIG. 19 illustrates a second side view, FIG. 20 illustrates a first end view and FIG. 21 illustrates a second opposing end view of user-assembled free weight 300. FIG. 22 is a section view of user-assembled free weight 300 taken through the section line indicated in FIG. 18 . Hollow container or mold 302 may be manufactured by blow molding and includes a single, contiguous material that has a main cavity 306 and a hollow handle 310 surrounded at least partially by main cavity 306. Hollow handle 310 is defined by a diameter 322 and includes an outer surface 316. Outer surface 316 may include a contiguous texture intended to improve grip for users. The texture may be manufactured as being part of handle 310 as is the case for handle 110 of free weight 100, however, the texture may also be provided by applying a grip surface to an exterior of handle 310, for example, with gripping tape. Under one embodiment, diameter 322 may be 1.5 inches.

Free weight 300 is in the three-dimensional shape of a polyhedron having a plurality of polygonal faces. In one embodiment and as illustrated in FIGS. 16-22 , container 302 approximates the shape of an octagonal prism including having eight rectangular sides bounded by two octagonal ends 307 and 309. It should be realized that other polyhedron shapes are possible including a hexagonal prism and the like. Each rectangular side of container 302 includes a length 312 and width 325 and each octagonal end 307 and 309 of container 302 includes a depth 314 and a height 315. Depth 314 and height 315 of octagonal ends 307 and 309 may or may not be equal. Under one embodiment, length 312 of each rectangular side may be approximately 13.8 inches, width 325 of each rectangular side may be approximately 4.0 inches and depth 314 and height 315 of octagonal ends 307 and 309 may be approximately 10.34 inches.

The walls of cavity 306 are formed so that through a center of container 302 and extending from a first rectangular side 360 to an opposing second rectangular side 362 and spaced apart from ends 307 and 309 is an access slot 364 for accessing outer surface 316 of handle 310. Access slot 364 is defined by a plurality of slot walls of cavity 306. First and second lengthwise slot walls 366 and 368 face each other and extend lengthwise along a portion of length 312 of first and second rectangular sides 362 and 364 and for an entirety of height 315 of octagonal ends 307 and 309 of container 302 between first rectangular side 360 and opposing second rectangular side 362. Third and fourth widthwise slot walls 370 and 372 face each other and extend widthwise for an entirety of width 325 of first rectangular side 360 and opposing second rectangular side 362 and for an entirety of height 315 of octagonal ends 307 and 309 of container 302 between first rectangular side 360 and opposing second rectangular side 362. Therefore, cavity 306 is not only defined by external walls including rectangular sides (such as 360 and 362) of container 302 and octagonal ends 307 and 309, but cavity 306 is also defined by slot walls including first and second slot walls 366 and 368 and third and fourth slot walls 370 and 372.

End 307 of cavity 306 includes an opening 332. Opening 332 in FIGS. 16-20 is illustrated as being round. However, other shapes are possible including rectilinear, non-rectilinear and oval shapes as long as opening 332 is wide enough to fit most curing material tools, such as a concrete trowel, and to allow for easy transfer of fill into the inside of container or mold 302 through opening 332. With opening 332 located through end 307 of cavity 306 of container 302, the opposing end 309 of cavity 306 and container 302 can provide a level side that is supported by the floor or ground to allow container 302 to stand vertically while pouring fill and letting fill dry or cure.

Opening 332 should not be wider than depth 314 and height 315 of end 307 and may be configured to receive a cap or lid so that after fill 304 is cured or dried, the non-removable fill is hidden or protected from environmental exposure. In other embodiments, the cap or lid is configured to retain removable fill, such as granulated material or liquid material, inside container 304. Under one embodiment, opening 332 includes a diameter 334. Diameter may be approximately 3.5 inches. Surrounding opening 332 is a lip 336 that protrudes from end 307 by a length 337. The protrusion of lip 336 may be curved or straight, but should include an angle so that if fill 304 does crack, cracked pieces do not come out of opening 332. As illustrated in FIG. 22 , fill 304 is located from end 309 to end 307. Fill 304 should not be filled inside lip 336.

A first end 311 of hollow handle is coupled to cavity 306 through third slot wall 370 and a second end 313 of hollow handle 310 is coupled to cavity 306 through fourth slot wall 372. This means that when fill 304 is being poured into opening 332, fill 304 moves throughout cavity 306 including through hollow handle 310. Between first end 311 of hollow handle 110 and third slot wall 370 is a first hollow flared portion 318. In one embodiment, first hollow flared portion 318 is a circular flare that couples first end 311 of hollow handle 310 to cavity 306. First hollow flared portion 318 includes a first open area located at an intersection 319 between cavity 306 and first hollow flared portion 318 and a second open area located at first end 311 of hollow handle 310. The first open area is calculated by finding the product of πr² where r is the radius of the circular opening of first hollow flared portion 318 at first cavity 306 and second open area is calculated by finding the product of πr² where r is the internal radius of hollow handle 310. As illustrated, first open area is greater than second open area. Sides of first hollow flared portion 318 include a curved taper or curved flare. It should be realized that a straight flare is also possible.

Between second end 313 of hollow handle 310 and fourth slot wall 372 is a second hollow flared portion 320. In one embodiment, second flared portion 320 is a circular flare that couples second end 313 of hollow handle 310 to cavity 306. Second hollow flared portion 320 includes a third open area located at an intersection 323 between cavity 306 and second hollow flared portion 320 and a fourth open area located at second end 313 of hollow handle 310. The third open area is calculated by finding the product of πr² where r is the radius of the circular opening of second hollow flared portion 320 at cavity 306 and fourth open area is calculated by finding the product of πr² where r is the internal radius of hollow handle 310. As illustrated, third open area is greater than fourth open area. Sides of second hollow flared portion 318 include a curved taper or curved flare. It should be realized that a straight flare is also possible.

Flared portions 318 and 320 create a secure bond for fill 304 to run into and out of hollow handle 310, to reduce pressure on the middle of handle 310 caused by fill 304 in cavity 306 and to act like a funnel in guiding fill 304 throughout the hollow interior of container 302.

As illustrated in FIG. 22 , while filling container 302 with fill 304, a first rebar core 340 may be placed down through hollow handle 310 and extend a height of or less than a height of cavity 306. First rebar core 340 may be best placed after fill 304 has filled ½ to ¾ of cavity 306 and handle. First rebar core 340 may also be used to eliminate air pockets and make sure fill 304 fills the entirety of the volume of the interior of container 302. First rebar core 340 is configured to take pressure off handle 110 and transfer pressure to rebar 140. Fill 104 is then less likely to crack when free weight 100 is dropped. In addition, a second and a third rebar cores 341 and 342 may also be placed in container 302 along with first rebar core 340. Second rebar core 341 may be placed between first interior wall 366 and a side of container 302 and third rebar core 342 may be placed between second interior wall 368 and an opposing side of container 302.

FIG. 23 is a perspective view illustrating a user-assembled free weight or weight plate 400 according to another embodiment. Free weight or weight plate 400 includes a container or mold 402, a heavy fill material 404 located inside container 402 and a fitting 401. FIG. 24 is a perspective view illustrating container 402 of free weight 400 without fill material 404 and without fitting 401. Under one embodiment, heavy fill material 404 is a curing material, such as concrete, that after being poured into container 402 cures inside container 402 and is non-removable from container 402. In other embodiments, heavy fill material 404 may be a granulated material, such as sand, or a liquid material, such as water. Container 402 is designed to fit a precise amount of fill 404 leading to or producing at least a target weight. Correct capacity is determined using the industry standard of 0.087 pounds per cubic inch of cured concrete. It should be understood that while empty container 402 and fitting 401 are the products shipped to the user, the assembled, completed product 400 includes container 402 permanently wrapped around fill 404 and fitting 401 permanently inserted into fill 404. In addition, it should be realized that the dimensions of container 402 may change to form weight plate 400 of any target weight is also possible.

In one embodiment, container 402 may be made of a plastic material including a thermoplastic such as high-density polyethylene (HDPE), acrylonitrile butadiene styrene (ABS), polycarbonate (PC) or low-density polyethylene (LDPE). Not only are these exemplary materials crack and scratch resistant, these exemplary materials will protect fill 404 as well as the floor in the event a weight plate is dropped. Regardless, the material of container 402 is thick enough to provide extra support for all corners of the container or mold when filled with fill 404.

FIG. 25 illustrates a section view of empty container 402, FIG. 26 illustrates a perspective view of empty container 402 without fill and fitting 401 exploded from empty container 402 and FIG. 27 illustrates a perspective view of empty container 402 without fill and fitting 401 assembled to empty container 402. Hollow container or mold 402 may be manufactured by blow molding and includes a single, contiguous material that has a main cavity 406. Hollow container 402 and therefore free weight 400 is in the three-dimensional shape of a cylinder including a first end 407, an opposing second end 409 and a curved surface 460 therebetween. It should be realized that other three-dimensional shapes are possible. Each of first end 407 and second end 409 includes a diameter or width 412 and curved surface 460 includes a height 415.

The walls of container 402 are formed so that through a center of container 402 and extending from second end 409 towards opposing first end 407 includes a slot having a slot wall 464. The slot having slot wall 464 is formed through a center of container 402 and extends into cavity 406. Slot wall 464 is circular and has a diameter or width 465 and a height 467. However, it should be realized that other shapes are possible. Diameter or width 465 of slot wall 464 is less than diameter or width 412 of the entirety of container 402. Height 467 of slot wall 464 may be less than height 415 of container 402. Therefore, cavity 406, configured to receive fill 404, is not only defined by external walls including curved surface 460 located between first end 407 and second end 409, but cavity 406 is also defined by slot wall 464.

First end 407 includes an opening 432. Opening 432 is illustrated as being circular or round. However, other shapes are possible including rectilinear, non-rectilinear and oval shapes as long as opening 432 is wide enough to fit most curing material tools, such as a concrete trowel, and to allow for easy transfer of fill into the inside of container or mold 402 through opening 432. Opening 432 should not be wider than width or diameter 412, should allow for the filling of the volume of cavity 406 and may be configured to receive a cap or lid so that after fill 404 is cured or dried, the non-removable fill is hidden or protected from environmental exposure. In other embodiments, the cap or lid is configured to retain removable fill, such as granulated material or liquid material, inside container 304.

Under one embodiment, opening 432 includes a diameter 434. Diameter 434 is less than diameter 412, which provides end 407 with a lip around the periphery of fill 404 when container 402 is filled with fill 404. The lip goes around fill 404 at first end 407 so as to keep fill 404 secure in container 402. While fill 404 is being filled into cavity 406 of container 402, fitting 401 is inserted into the slot defined by slot wall 464. In FIGS. 24, 26 and 27 , fitting 401 is cylindrical and includes a diameter that is less than slot wall 464 so that fitting 401 may fit inside the slot and includes a height that is greater than height 467 of slot wall 464. In particular, the height of fitting 401 may be greater than height 415 of container 402, but also could be less than height 415 as long as fitting is as great as the distance between second 409 and the inner facing wall 469 of first end 407 or as great as the height of cavity 406 configured to receive fill 404. Fitting 401 not only protects fill 404, but it will also allow weight plate 400 to slide and off a weight bar (not illustrated). Fitting 401 may be made of polyvinyl chloride (PVC) or similar plastic material.

FIG. 28 is a first end perspective view illustrating a user-assembled free weight or dumbbell 500 according to another embodiment. FIG. 29 is an opposing second end perspective view of user-assembled free weight or dumbbell 500. Free weight or dumbbell 500 includes a container or mold 502 and a heavy fill material (not illustrated in FIGS. 28-33 ) located inside container 502. Under one embodiment, the heavy fill material is a curing material, such as concrete, that after being poured into container 502 cures inside container 502 and is non-removable from container 502. In other embodiments, the heavy fill material may be a granulated material, such as sand, or a liquid material, such as water. Container 502 is designed to fit a precise amount of fill leading to or producing at least a target weight. For example, FIGS. 28-33 illustrate container 502 that will ultimately weigh about 80 pounds when filled with concrete. Correct capacity is determined using the industry standard of 0.087 pounds per cubic inch of cured concrete. It should be understood that while empty container 502 is the product shipped to the user, the assembled, completed product 500 includes plastic container 502 permanently wrapped around fill 504. In addition, it should be realized that the dimensions of container 502 may change to form dumbbell 500 of any target weight is also possible.

In one embodiment, container 502 may be made of an opaque material, transparent material or have some degree of transparency. Material made of a transparent or some degree of transparency allows the user to visually see fill moving down container or mold 502 during the fill or pour to ensure there are no air pockets. The user can either shake the container while it is filling to ensure no air spaces or use a tool, such as an elongated stick. For example, container 502 may be made of a plastic including a thermoplastic such as high-density polyethylene (HDPE), acrylonitrile butadiene styrene (ABS), polycarbonate (PC) or low-density polyethylene (LDPE). Not only are these exemplary materials crack and scratch resistant, these exemplary materials will protect the fill as well as the floor in the event a dumbbell is dropped. Regardless, the material of container 502 is thick enough to provide extra support for all corners of the container or mold when filled with fill.

FIG. 30 is a side view of user-assembled free weight 500. FIG. 31 is a bottom view of user-assembled free weight 500. FIG. 32 is a section view of user-assembled free weight 500 taken through the section line illustrated in FIG. 29 . FIG. 33 is a section view of user-assembled free weight 500 taken through the section line illustrated in FIG. 31 . Hollow container or mold 502 may be manufactured by blow molding and is made of a single, contiguous material. Container 502 includes a length 512, a width 514 and a height 515.

Container 502 includes a first end cavity 506 having an opening 532 for access into the interior of container 502, a second closed end cavity 508 and a hollow handle 510. Hollow handle 510 is defined by a diameter and includes an outer surface that may include a contiguous texture intended to improve grip for users. The texture may be manufactured as being part of handle 510, however, the texture may also be provided by applying a grip surface to an exterior of handle 510, for example, with gripping tape. Under one embodiment, diameter of handle 510 may be about 1.3 to 1.5 inches.

First end cavity 506 is defined between a first end wall 507 having opening 532 and a first widthwise wall 570 and between a first side wall 560 and a second side wall 562. Second end cavity 508 is defined between a second closed end wall 509 and a second widthwise wall 572 and between first side wall 560 and second side wall 562. A first connecting cavity 561 connects first end cavity 506 to second end cavity 508 and is defined between first side wall 560 and a first lengthwise wall 566. A second connecting cavity 563 spaced apart from first connecting cavity 561 also connects first end cavity 506 to second end cavity 508 and is defined between second side wall 562 and a second lengthwise wall 568. Handle 510 extends between first widthwise wall 570 and second widthwise wall 572 and is spaced apart and located in between first lengthwise wall 566 and second lengthwise wall 568.

As illustrated, first and second connecting cavities 561 and 563 include a height 565. Height 565 is less than a height 515 of each of first and second end cavities 506 and 508. In addition, first connecting cavity 561, second connecting cavity 563 and hollow handle 510 all extend from a center of height 515 of each of first end cavity 506 and second end cavity 508. FIG. These structural features of user-assembled free weight 500 serve a particular function of allowing a user to grip handle 510 of weight 500 in either a left hand or a right hand and hold the weight next to the side of their body, for example, adjacent to the lateral side of a user's thighs of their legs in order to perform certain weight bearing exercises including lunges, squats and bicep curls. In other words, the space created by having first and second connecting cavities 561 and 563 shorter than first and second end cavities 506 and 508 fits against the side of the user's hips or legs.

As previously described, first end wall 507 includes opening 532. Opening 532 in FIGS. 28-33 is illustrated as being round. However, other shapes are possible including rectilinear, non-rectilinear and oval shapes as long as opening 532 is wide enough to fit most curing material tools, such as a concrete trowel, and to allow for easy transfer of fill into the inside of container or mold 502 through opening 532. With opening 532 located through first end wall 507 of container 502, the opposing second end wall 509 of container 502 can provide a level side that is supported by the floor or ground to allow container 502 to stand vertically while pouring fill and letting fill dry or cure. Surrounding opening 532 is a lip 536 that protrudes from first end wall 507 by a length 537. The protrusion of lip 536 may be curved or straight, but should include an angle so that if fill does crack, cracked pieces do not come out of opening 532.

As illustrated in FIGS. 32 and 33 , each of first end wall 507, second end wall 509, first side wall 560, second side wall 562, first widthwise wall 570, second widthwise wall 572, first lengthwise wall 566 and second lengthwise wall 568 include outer facing surfaces and inner facing surfaces. In particular, an inner facing surface of first end wall 507 faces an inner facing surface of first widthwise wall 570, an inner facing surface of second end wall 509 faces an inner facing surface of second widthwise wall 572, an inner facing surface of first side wall 560 faces inner facing surface of first lengthwise wall 566 and an inner facing surface of second side wall 562 faces inner facing surface of second lengthwise wall 568. FIG. 33 further illustrates a phantom dashed line indicated the location of opening 532 in first end wall 507 (hidden from view). As illustrated in FIGS. 28 and 30-33 , a width or diameter of opening 532 is less than a height and a width of first end wall 507. As illustrated in FIGS. 32 and 33 by the dashed lines, opening 532 may have a width or diameter that is at least as great as a distance 567 between first lengthwise wall 566 and second lengthwise wall 568. This width or diameter of opening 532 allows fill being poured into opening 532 to fill and move quickly and with ease throughout the interior of container 502 including through hollow handle 510, first connecting cavity 561 and second connecting cavity 563.

FIG. 34 is a first end perspective view illustrating a user-assembled free weight or dumbbell 600 according to another embodiment. FIG. 35 is an opposing second end perspective view of user-assembled free weight or dumbbell 600. Free weight or dumbbell 600 includes a container or mold 602 and a heavy fill material 604 located inside container 602. Under one embodiment, the heavy fill material is a curing material, such as concrete, that after being poured into container 602 cures inside container 602 and is non-removable from container 602. In other embodiments, the heavy fill material may be a granulated material, such as sand, or a liquid material, such as water. Container 602 is designed to fit a precise amount of fill leading to or producing at least a target weight. For example, FIGS. 34-39 illustrate container 602 that will ultimately weigh about 60 pounds when filled with concrete. Correct capacity is determined using the industry standard of 0.087 pounds per cubic inch of cured concrete. It should be understood that while empty container 602 is the product shipped to the user, the assembled, completed product 600 includes plastic container 602 permanently wrapped around fill 604. In addition, it should be realized that the dimensions of container 602 may change to form dumbbell 600 of any target weight is also possible.

In one embodiment, container 602 may be made of an opaque material, transparent material or have some degree of transparency. Material made of a transparent or some degree of transparency allows the user to visually see fill moving down container or mold 602 during the fill or pour to ensure there are no air pockets. The user can either shake the container while it is filling to ensure no air spaces or use a tool, such as an elongated stick. For example, container 602 may be made of a plastic including a thermoplastic such as high-density polyethylene (HDPE), acrylonitrile butadiene styrene (ABS), polycarbonate (PC) or low-density polyethylene (LDPE). Not only are these exemplary materials crack and scratch resistant, these exemplary materials will protect the fill as well as the floor in the event a dumbbell is dropped. Regardless, the material of container 602 is thick enough to provide extra support for all corners of the container or mold when filled with fill.

FIG. 36 is a side view of user-assembled free weight 600. FIG. 37 is a bottom view of user-assembled free weight 600. FIG. 38 is a section view of user-assembled free weight 600 taken through the section line illustrated in FIG. 35 . FIG. 39 is a section view of user-assembled free weight 600 taken through the section line illustrated in FIG. 37 . Hollow container or mold 602 may be manufactured by blow molding and is made of a single, contiguous material. Container 602 includes a length 612, a width 614 and a height 615.

Container 602 includes a first end cavity 606 having an opening 632 for access into the interior of container 602, a second closed end cavity 608 and a hollow handle 610. Hollow handle 610 is defined by a diameter and includes an outer surface that may include a contiguous texture intended to improve grip for users. The texture may be manufactured as being part of handle 610, however, the texture may also be provided by applying a grip surface to an exterior of handle 610, for example, with gripping tape. Under one embodiment, diameter of handle 610 may be about 1.3 to 1.5 inches.

First end cavity 606 is defined between a first end wall 607 having opening 632 and a first widthwise wall 670 and between a first side wall 660 and a second side wall 662. Second end cavity 608 is defined between a second closed end wall 609 and a second widthwise wall 672 and between first side wall 660 and second side wall 662. A first connecting cavity 661 connects first end cavity 606 to second end cavity 608 and is defined between first side wall 660 and a first lengthwise wall 666. A second connecting cavity 663 spaced apart from first connecting cavity 661 also connects first end cavity 606 to second end cavity 608 and is defined between second side wall 62 and a second lengthwise wall 668. Handle 610 extends between first widthwise wall 670 and second widthwise wall 672 and is spaced apart and located in between first lengthwise wall 666 and second lengthwise wall 668. As illustrated, first and second connecting cavities 661 and 663 include a height 665. Height 665 is less than a height 615 of each of first and second end cavities 606 and 608. In addition, first connecting cavity 661, second connecting cavity 663 and hollow handle 610 all extend from a center of height 615 of each of first end cavity 606 and second end cavity 608.

FIG. 40 illustrates a user holding handle 610 of free weight 600 under an embodiment. The structural features of user-assembled free weight 600 serve a particular function of allowing a user to grip handle 610 of weight 600 in either a left hand or a right hand and hold the weight next to the side of their body, for example and as illustrated in FIG. 40 , adjacent to the lateral side of a user's thighs of their legs in order to perform certain weight bearing exercises including lunges, squats and bicep curls. In other words, the space created by having first and second connecting cavities 661 and 663 shorter than first and second end cavities 606 and 608 fits against the side of the user's hips or legs.

As previously described, first end wall 607 includes opening 632. Opening 632 in FIGS. 34-39 is illustrated as being round. However, other shapes are possible including rectilinear, non-rectilinear and oval shapes as long as opening 632 is wide enough to fit most curing material tools, such as a concrete trowel, and to allow for easy transfer of fill into the inside of container or mold 602 through opening 632. With opening 632 located through first end wall 607 of container 602, the opposing second end wall 609 of container 602 can provide a level side that is supported by the floor or ground to allow container 602 to stand vertically while pouring fill and letting fill dry or cure. Surrounding opening 632 is a lip 636 that protrudes from first end wall 607 by a length 637. The protrusion of lip 636 may be curved or straight, but should include an angle so that if fill does crack, cracked pieces do not come out of opening 632.

As illustrated in FIGS. 38 and 39 , each of first end wall 607, second end wall 609, first side wall 660, second side wall 662, first widthwise wall 670, second widthwise wall (not shown in FIGS. 38 and 39 ), first lengthwise wall 666 and second lengthwise wall 668 include outer facing surfaces and inner facing surfaces. In particular, an inner facing surface of first end wall 607 faces an inner facing surface of first widthwise wall 670, an inner facing surface of second end wall 609 faces an inner facing surface of second widthwise wall 672, an inner facing surface of first side wall 660 faces inner facing surface of first lengthwise wall 666 and an inner facing surface of second side wall 662 faces inner facing surface of second lengthwise wall 668. FIG. 39 further illustrates a phantom dashed line indicated the location of opening 632 in first end wall 607 (hidden from view). As illustrated in FIGS. 34 and 36-39 , a width or diameter of opening 632 is less than a height and a width of first end wall 607. As illustrated in FIGS. 38 and 39 by the dashed lines, opening 632 may have a width or diameter that is at least as great as a distance 667 between first lengthwise wall 666 and second lengthwise wall 668. This width or diameter of opening 632 allows fill being poured into opening 632 to fill and move quickly and with ease throughout the interior of container 602 including through hollow handle 610, first connecting cavity 661 and second connecting cavity 663.

At least one of first lengthwise wall 666 and second lengthwise wall 668 includes a recess having an arcuate surface. As illustrated in FIGS. 34, 35, 37, 38 and 39 , first lengthwise wall 666 includes a recess 669 in an outer facing surface that faces handle 610 and second lengthwise wall 668 includes a recess 671 in an outer facing surface that faces handle 610. Recess 669 and recess 671 are arcuate recessed surfaces. One of recesses 669 and 671 is configured to engage with an outer surface of a barbell.

FIG. 41 is a front perspective view of two of the user-assembled free weights 600 in a configuration where they are engaged with a barbell 780 according to an embodiment. FIG. 42 is a side perspective of FIG. 41 . As illustrated, the distance or space between handle 610 and first lengthwise wall 666 and the distance or space between handle 610 and second lengthwise wall 668 allow free weight 600 to slide directly onto barbell 780. For example, free weight 600 is configured to slide on a standard barbell with a 2 inch diameter at a location between handle 610 and first lengthwise wall 666 of free weight 600 or is configured to slide on a standard barbell with a 2 inch diameter at a location between handle 610 and second lengthwise wall 668 of free weight 600. Depending on how the two free weight 600 slide on barbell 780, each free weight 600 rests on the barbell or engages with an outer surface of the barbell at one of recess 669 or recess 671. The symmetrical nature of free weight 600 and the arcuate surfaces of recesses 669 and 671 keeps free weights 600 from sliding left or right and off of barbell 780. If more than one free weight 600 is slid onto each end of barbell to add additional weight, a clamp may be used to keep the free weights 600 in place on the barbell.

It should be recognized that while free weight 600 was described as having a target weight of 60 pounds, the design of free weight 600 may be applied to other target weights including for example, 25 pounds or 100 pounds to name only a couple possibilities.

Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. 

What is claimed is:
 1. A user-assembled free weight comprising: a hollow container made of a contiguous material and having a length, a width and a height, the hollow container comprising: a first end wall that includes an opening for access into an interior of the container; a second opposing closed end wall; a first side wall that extends from the first end wall to the second end wall and defines the length of the container; an opposing second side wall spaced apart from the first side wall, extends from the first end wall to the second end wall and defines the length of the container; a first widthwise wall spaced apart from the first end wall to define the interior of the container; a second widthwise wall spaced apart from the second end wall to define the interior of the container; a first lengthwise wall spaced apart from the first side wall to define the interior of the container and connecting the first widthwise wall to the second widthwise wall; a second lengthwise wall spaced apart from the second side wall to define the interior of the container and connecting the first widthwise wall to the second widthwise wall; a hollow handle that extends from the first widthwise wall to the second widthwise wall and is spaced apart from the first lengthwise wall and from the second lengthwise wall; and a heavy curable material placed inside the container through the opening in the first end wall, the heavy curable fill material being located inside the container and the handle and being non-removable; and wherein the opening in the first end wall has a width that is less than a width of the first end wall and at least as great as a distance between the first lengthwise wall and the second lengthwise wall.
 2. The user-assembled free weight of claim 1, wherein the opening in the first end wall is surrounded by a lip that protrudes outwardly from the first end wall.
 3. The user-assembled free weight of claim 1, wherein the width of opening in the first end wall is greater than the distance between the first lengthwise wall and the second lengthwise wall.
 4. The user-assembled free weight of claim 1, wherein the first lengthwise wall and the second lengthwise wall extend an entirety of the height of the container.
 5. The user-assembled free weight of claim 1, wherein the first lengthwise wall and the second lengthwise wall extend a portion of the height of the container.
 6. The user-assembled free weight of claim 1, wherein the first side wall and the second side wall have a first height where the first side wall intersects the first end wall and where the second side wall intersects the second end wall and wherein the first side wall and the second side wall have a second height that is less than the first height where the first lengthwise wall and the second lengthwise wall extend from the first widthwise wall to the second widthwise wall.
 7. The user-assembled free weight of claim 1, wherein the first lengthwise wall comprises an outer facing surface having a recessed arcuate surface, the recessed arcuate surface of the first lengthwise wall faces the handle.
 8. The user assembled free weight of claim 7, wherein the second lengthwise wall comprises an outer facing surface having a recessed arcuate surface, the recessed arcuate surface of the second lengthwise wall faces the handle.
 9. The user-assembled free weight of claim 8, wherein the recessed arcuate surface of the first lengthwise wall is configured to engage with an outer surface of a barbell and the recessed arcuate surface of the second lengthwise wall is configured to engage with an outer surface of a barbell.
 10. A user-assembled free weight comprising: a hollow container made of a contiguous material and comprising: a first end cavity defined between a first end wall having an opening for access into an interior of the container and a first widthwise wall and between a first side wall and a second side wall; a second closed end cavity defined between a second closed end wall and a second widthwise wall and between the first side wall and the second side wall; a first connecting cavity that connects the first end cavity to the second end cavity and is defined between the first side wall and a first lengthwise wall; a second connecting cavity spaced apart from the first connecting cavity that connects the first end cavity to the second end cavity and is defined between the second side wall and a second lengthwise wall; a hollow handle that extends from the first widthwise wall to the second widthwise wall and is spaced apart and located between the first lengthwise wall and the second lengthwise wall; and a heavy curable material placed inside the container through the opening in the first end wall, the heavy curable fill material being located inside the container and the handle and being non-removable; and wherein a height of the first connecting cavity and the second connecting cavity are less than a height of the first end cavity and the second end cavity.
 11. The user-assembled free weight of claim 10, wherein the first connecting cavity, the second connecting cavity and the hollow handle extend from a center of the height of the first end cavity and the second end cavity.
 12. The user-assembled free weight of claim 10 wherein at least one of the first lengthwise wall and the second lengthwise wall has an outer facing surface that faces the hollow handle and includes a recess having an arcuate surface.
 13. The user-assembled free weight of claim 12, wherein the arcuate surface of the recess is configured to engage with an outer surface of a barbell.
 14. The user-assembled free weight of claim 10, wherein the opening in the first end wall has a width that is less than a width and a height of the first end wall and at least as great as a distance between the first lengthwise wall and the second lengthwise wall.
 15. The user-assembled free weight of claim 10, wherein the opening in the first end wall is surrounded by a lip that protrudes outwardly from the first end wall.
 16. A user-assembled free weight comprising: a hollow container made of a contiguous material and comprising: a first end cavity defined between a first end wall having an opening for access into an interior of the contain and a first widthwise wall and between a first side wall and a second side wall; a second closed end cavity defined between a second closed end wall and a second widthwise wall and between the first side wall and the second side wall; a first connecting cavity that connects the first end cavity to the second end cavity and is defined between the first side wall and a first lengthwise wall; a second connecting cavity spaced apart from the first connecting cavity that connects the first end cavity to the second end cavity and is defined between the second side wall and a second lengthwise wall; a hollow handle that extends from the first widthwise wall to the second widthwise wall and is spaced apart and located between the first lengthwise wall and the second lengthwise wall; and a heavy curable material placed inside the container through the opening in the first end wall, the heavy curable fill material being located inside the container and the handle and being non-removable; and wherein at least one of the first lengthwise wall and the second lengthwise wall has an outer facing surface that faces the hollow handle and includes a recess having an arcuate surface.
 17. The user-assembled free weight of claim 16, wherein the arcuate surface of the recess is configured to engage with an outer surface of a barbell.
 18. The user-assembled free weight of claim 16, wherein the opening in the first end wall has a width that is less than a width and a height of the first end wall and at least as great as a distance between the first lengthwise wall and the second lengthwise wall.
 19. The user-assembled free weight of claim 16, wherein the opening in the first end wall is surrounded by a lip that protrudes outwardly from the first end wall.
 20. The user-assembled free weight of claim 16, wherein a height of the first connecting cavity and the second connecting cavity are less than a height of the first end cavity and the second end cavity. 